fix: add check, if user has pnmp, before installing frontend dependencies and update Dockerfile to use devforth/node20-pnpm image for the dev-demo

Author: yaroslav8765

adminforth/package.json

@@ -20,7 +20,7 @@
     "rollout-doc": "cd documentation && pnpm build && pnpm deploy",
     "docs": "typedoc",
     "--comment_postinstall": "postinstall executed after package installed in other project package and when we do pnpm i in the package",
-    "postinstall": "node -e \"const fs=require('fs');const path=require('path');const spaPath=path.join(__dirname,'dist','spa');if(fs.existsSync(spaPath) && !process.env.PNPM_INSTALL_SPA){process.env.PNPM_INSTALL_SPA=1;require('child_process').execSync('pnpm install --frozen-lockfile',{cwd:spaPath,stdio:'inherit'});console.log('installed spa dependencies');}\""  
+    "postinstall": "node scripts/postinstall.js"  
    },
   "release": {
     "plugins": [

adminforth/scripts/postinstall.js

@@ -0,0 +1,25 @@
+import fs from 'node:fs';
+import path from 'node:path';
+import { fileURLToPath } from 'node:url';
+
+const nodeBinary = process.execPath;
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = path.dirname(__filename);
+const spaPath=path.join(__dirname,'dist','spa');
+
+const pnpmPotentionalPath=path.join(nodeBinary,'..','pnpm');
+const doesUserProjectHasPnpm = fs.existsSync(pnpmPotentionalPath)
+console.log('doesUserProjectHasPnpm', doesUserProjectHasPnpm);
+if (doesUserProjectHasPnpm) {
+  if(fs.existsSync(spaPath) && !process.env.PNPM_INSTALL_SPA){
+    process.env.PNPM_INSTALL_SPA=1;
+    require('child_process').execSync('pnpm install --frozen-lockfile',{cwd:spaPath,stdio:'inherit'});
+  }
+} else {
+  if(fs.existsSync(spaPath)){
+    process.chdir(spaPath);
+    require('child_process').execSync('npm ci',{stdio:'inherit'});
+  }
+}
+
+console.log('installed spa dependencies');